Spinal Cord Flashcards
What are the meninges?
-Meninges = “membranes”
-Connective tissue membranes covering the brain
Where are the meninges?
External to brain & spinal cord
What are the 3 meninges enveloping the brain & spinal cord (CNS)?
-Dura mater = CT –> most superficial
1.Periosteal layer
2. Meningeal layer
-Arachnoid mater
-Pia mater –> deepest
Describe the dura mater.
-Thick
-Tough
What are dural folds/reflections?
Form from inward folding of meningeal layer of dura mater into cranial cavity
Name the dural folds/reflections & where they are.
-Falx cerebri = divides R & L cerebral hemispheres
-Diaphragma sellae = has hole for pituitary gland stalk to pass through
-Falx cerebelli – divides R & L cerebellar hemispheres
-Tentorium cerebelli – divides occipital lobes & cerebellum – has an opening called the tentorial notch
What are the names of the spaces in the meninges of the brain?
What are the names of the spaces in the meninges of the spinal cord?
Describe the arachnoid mater.
-Middle meningeal layer
-Avascular
-Has arachnoid granules
What are arachnoid granules?
Protrusions of arachnoid mater into the dural venous sinuses – for CSF to re-enter this venous circulation
Describe the pia mater.
-Most deep meningeal layer
-Vascularised - contains meningeal arteries
-Adheres to brain & spinal cord surfaces
–> follows gyri & sulci of brain
-Transparent
What are gyri & sulci?
-Gyrus = folded cortex – upward ridges
-Sulcus = groove – inward fissure
Name the layers of the head.
Name the 5 different regions of the spine & how many vertebrae are in each.
Functions of the spinal column?
-Provide support for body & foundation for posture
-Provide flexibility - separation into individual vertebrae allows for bending & twisting
-Protect spinal cord & spinal nerve roots
What are the 2 general regions of a vertebrae?
-Vertebral body
-Vertebral arch
What part of a vertebrae does the spinal cord pass through?
Vertebral foramen
What can the vertebral arch be further divided into?
-Spinous process
-Lamina
-Superior articular process
-Pedicles
-Transverse process
Label this typical thoracic vertebrae.
What is found in between each vertebrae (if not fused)?
Fibrocartilage intervertebral disc
Name the facets used by a typical vertebrae to articulate with the vertebrae above & below.
-Superior articular facets
-Inferior articular facets
–> found on articular processes
Label.
How many vertebrae are there?
33
How many spinal nerves are there?
31 pairs
How many of each type of spinal nerves are there?
Cervical region - number of vertebrae & spinal nerves?
-Vertebrae = 7
-Spinal nerves = 8
Where do spinal nerves exit between vertebrae?
Intervertebral foramen
Location in relation to the vertebrae that the spinal nerves exit at?
-Exit below the corresponding vertebra.
***Except in the cervical region - where they exit
above the corresponding vertebrae
e.g., spinal nerve - thoracic 6 exits below thoracic vertebra 6 - whereas spinal nerve - cervical 3 exits above cervical vertebra 3
Structure of sacrum & coccyx?
Structure of typical cervical vertebrae?
-Triangular vertebral foramen
-Bifid (two-pronged) spinous process
-Small vertebral body
-Transverse foramina
Purpose of transverse foramina?
For passage of vertebral arteries
Structure of typical thoracic vertebrae
-Articulate with the ribs, and so each
typical vertebra has:
*Costal facet – on transverse process
*Superior & inferior demi-facets – on vertebral
body
Structure of typical lumbar vertebrae?
-Triangular vertebral foramen
-‘Kidney-shaped’ vertebral body
-Thick vertebral arch
-Are the largest vertebrae
Describe how a thoracic vertebrae articulates with each other & to the ribs.
e.g., T4
*Costal facet of T4 articulates with 4th rib tubercle
*Superior demi-facet of T4 articulates with 4th rib head
*Inferior demi-facet of T4 articulates with 5th rib head
*Superior articular facets - articulate with T3
*Inferior articular facets - articulate with T5
Name the atypical thoracic vertebrae.
T1, T9, T10, T11, T12
Why is T1 an atypical thoracic vertebrae?
Has complete superior facet as rib I does not articulate at all with C7
And demi-facet for rib 2
Straighter spinous process
Why is T9 an atypical thoracic vertebrae?
No inferior demi-facet -> only connects with rib 9 head (NOT 10)!
Why are T10, T11 & T12 atypical thoracic vertebrae?
-T10-12 have full superior facets & lack inferior
demi-facets - as ribs X, XI, & XII only articulate with their corresponding vertebrae
-T11 and 12 do not have costal facets - as floating ribs do not articulate with transverse processes
Give the 3 atypical cervical vertebrae - & what else they are called.
Why is C1 - atlas an atypical cervical vertebrae?
-No vertebral body - instead has anterior arch
-x2 superior facets for articulation with occipital
condyles
-Short, non-bifid spinous process
Why is C2 - axis an atypical cervical vertebrae?
-Lacks a vertebral body - instead has a dens (or odontoid process)
What is the atlanto-axial joint?
Joint between C1 (atlas) & C2 (axis)
-Dens/odontoid process projects superiorly & sits flush with anterior vertebral arch
–> permits horizontal pivoting – so can shake head
Why is C7 - vertebra prominens an atypical cervical vertebrae?
-Long, prominent, non-bifid spinous process.
(Easily palpable – can feel if flex neck)
What are the 6 sets of spinal ligaments?
-Anterior longitudinal ligament
-Posterior longitudinal ligament
-Ligamentum flavum
-Interspinal ligament
-Supraspinous ligament
-Intertransverse ligament
Where is the anterior longitudinal ligament & what does it do?
Along anterior aspect of vertebral column – over vertebral bodies & intervertebral discs –> prevents hyperextension of spine
Where is the posterior longitudinal ligament & what does it do?
Along posterior aspect of vertebral column – over vertebral bodies & intervertebral discs –> prevents hyperflexion of spine
Where is the ligamentum flavum & what does it do?
Between/connect laminae of vertebrae –> prevents hyperflexion of spine & stops rotation by holding laminae together
Where is the interspinal ligament & what does it do?
Between/connect spinous processes of adjacent vertebrae –> prevents hyperflexion of spine & holds spinous processes together
Where is the supraspinous ligament & what does it do?
Along posterior aspect of vertebrae –> prevents hyperflexion of spine
Where is the intertransverse ligament?
Between/attach transverse processes of adjacent vertebrae –> holds these together & prevent lateral flexion of spine
What ligament is the supraspinous ligament a continuation of?
Nuchal ligament of the neck
Role of the nuchal ligament of the neck?
Prevents head lolling forwards - without energy
of muscular exertion
What is the dentate/denticulate ligament?
Extension/continuation/lateral projections of pia mater
-> bilateral triangular lateral extensions
-Runs down spinal cord
-Firmly attach arachnoid mater to dura mater at apex
-Originate on either side of spinal cord -> stops spinal cord moving laterally
What is the conus medullaris?
-Terminal part of spinal cord – called this as is cone shaped
-> L1/2-S5 & coccygeal element
-Tethered to coccyx by filum terminale
What is the filum terminale?
Joins conus medullaris to coccyx
What is the cauda equina?
“Spinal nerve roots (L2-S5 & Co), coccygeal nerve (Co)”
–> collection of spinal nerve roots
–> nerve pairs exiting vertebral column from L2, L3, L4, L5, S1, S2, S3, S4, S5, Co - extend down inside vertebral column & then exit out @ appropriate vertebral level
-Looks like horses tail
What is the lumbar cistern?
-Enlargement of subarachnoid space in lower lumbar spinal canal -> contains CSF
-Between L1-S2 vertebrae
What is the foramen magnus?
-Foramen = ‘hole’
-Largest foramen in skull
= where the spinal cord continues on from the brain
–> along with “passage of meninges; vertebral arteries, anterior & posterior spinal arteries, dural veins”
Where is CSF found?
-Found in subarachnoid space & ventricular system (in ventricles of brain)
-Made by choroid plexus
Functions of CSF?
-Protection – as acts as shock absorber – cushioning brain
-Waste enters from brain cells into CSF – which then drains into venous circulation
-Surrounds brain with metabolites – for nourishment
Describe the flow of CSF.
-CSF = made by choroid plexus
Choroid plexus -> lateral ventricles -> foramen of Monroe/interventricular foramen -> 3rd ventricle -> cerebral aqueduct -> 4th ventricle – then either:
-> through lateral apertures/foramen of Luschka -> into central canal of spinal cord subarachnoid space
OR
-> through median aperture/foramen of Magendie -> cisterna magna - i.e., passes to cranial subarachnoid space -> eventually enters dural venous circulation – via arachnoid granules – into dural venous sinuses
Label the ventricles of the brain.
What is each lateral ventricle divided into?
-Anterior horn
-Body
-In parietal lobe
-Posterior horn
-Extends to the occipital lobe
-Inferior horn
-Projects toward the temporal lobe
What part of a lateral ventricle is this?
What part of a lateral ventricle is this?
What part of a lateral ventricle is this?
What part of a lateral ventricle is this?
What is this joining onto the lateral ventricles?
Describe the 3rd ventricle.
Cavity located in between the right & left thalami
How does the 3rd ventricle communicate with the 4th ventricle?
Via:
cerebral aqueduct/aqueduct of Sylvius
What are the lateral apertures/foramen of Luschka - of the 4th ventricle?
= small openings on both sides of 4th
ventricle - allow CSF to drain from 4th ventricle
to central canal of spinal cord subarachnoid space
What are the median apertures/foramen of Magendie - of the 4th ventricle?
-Small opening/hole - on postero-inferior side of 4th ventricle
-Allows CSF to pass into cranial subarachnoid space
What are the 2 parts making up the intervertebral disc?
-Nucleus pulposus
-Anulus fibrosus
What 2 types of joints are present between vertebrae?
Secondary cartilaginous joints = symphyses
Label this cross-section of the spinal cord.
Label this cross-section of the spinal cord.
Describe distinctive features of the cervical spinal cord.
Larger in transverse plan than in sagittal plane - i.e., is wide & thin
Describe distinctive features of the thoracic spinal cord.
-Has lateral horn of grey matter (not found anywhere else)
-Has smaller ventral horn than other regions of spinal cord - as spinal nerves derived from thoracic spinal cord DO NOT innervate the limbs (cervical inn = upper limbs, lumbar & sacral = inn lower limbs) - so in thoracic is a smaller ventral horn as thoracic neurones only innervate the trunk - so are fewer motor neurones exiting & synapsing here so are fewer motor neurones in this ventral horn = smaller
How to differentiate the lumbar and sacral spine?
When have both to compare - lumbar = larger & sacral = smaller
Otherwise - use proportion of grey:white matter
-Lumbar = greater proportion of white than grey matter
-Sacral = greater proportion of grey than white matter
—> a pattern seen down spinal cord - decrease in white matter - as are fewer ascending & descending axons (which make up white matter)
(So cervical = most white matter - down to sacral with the least - as higher up - white matter tracts pass from brain to everything below & passing sensory info to brain from everything below)
What is a herniated disc?
Fragment of disc nucleus - is pushed out of annulus (inner gelatinous centre of intervertebral disc) into the spinal canal through a tear or rupture in the annulus (tougher outer layer of intervertebral disc)
Symptoms of herniated disc?
-Top 4 = general symptoms
-Bottom 4 = specific to cervical spine (lower neck) as the site of the herniated disc
Treatments for herniated discs?
If no improvements shown then spinal surgery may be needed:
-Discectomy
-Laminectomy
What label indicates T4?
B
Which label indicates the lamina of the vertebra?
D
Which label indicates the dorsal/posterior ramus of the spinal nerve?
C
Which label indicates the supraspinous ligament?
E
Which label indicates the subarachnoid space?
C
Which label indicates the least splanchnic nerve?
H
Which label indicates dermatome L2?
D
Which label indicates the pedicle of the vertebra?
B
Which label indicates a sympathetic ganglion?
E
Which label indicates the ligamentum flava?
D
Which label indicates where an epidural injection would be administered?
A
Which label indicates the sacral plexus (L4/5, S1-4)?
D
Which label indicates dermatome T10?
C
Which label indicates the vertebral body?
A
Which label indicates dorsal root ganglion of the spinal nerve?
B
Which label indicates posterior longitudinal ligament?
A
Which label indicates the denticulate ligament?
D
Which label indicates the lateral ventricle?
F
Which label indicates dermatome S1?
F
Which label indicates the spinous process of the vertebra?
E
Which label indicates the anterior/ventral root of the spinal nerve?
F
Which label indicates the interspinous ligament?
F
Which label indicates the toughest of the meningeal layers?
G
Which label indicates the greater splanchnic nerve (T5-T9)?
F
Which label indicates dermatome T1?
A
Which label indicates the transverse process?
C
Which label indicates ventral/anterior ramus of the spinal nerve?
D
Which label indicates the dura mater of the spinal cord?
B
Which label indicates the centre of production of cerebrospinal fluid (CSF)?
E = choroid plexus
Which label indicates the vagus nerve?
E
Label.
Label the dermatomes.
